【单选题】患者男性,70岁,呼吸困难7天。查体:右肺叩实,呼吸音消失,B超示右侧大量胸腔积液。胸腔穿刺抽出血性胸水,胸水找癌细胞及抗酸杆菌均阴性。最可能的诊断是:
【判断题】The main analytical techniques used for determination of trace elements in environmental samples include: Atomic absorption spectrometry (flame or electrothermal) (AAS, ET-AAS), atomic fluorescence sp...
【单选题】根据无刷电动机的特殊情况,用于改变电枢电压的调速方法是( )。
B.
用他励直流发电机调整供给直流电动机的电枢电压
D.
用电子换向开关电路,每相导通时间维持不变,改变每相导通时加在线圈上的电压幅度大小来实现调速。
【单选题】根据无刷电动机的特殊情况,用于改变电枢电压的调速方法是( )。
B.
用他励直流发电机调整供给直流电动机的电枢电压
D.
用电子换向开关电路,每相导通时间维持不变,改变每相导通时加在线圈上的电压幅度大小来实现调速
【判断题】The main analytical techniques used for determination of trace elements in environmental samples include: Atomic absorption spectrometry (flame or electrothermal) (AAS, ET-AAS), atomic fluorescence sp...
【简答题】Serum containing Na + gave a signal of 4.27 mv in an atomic emission ysis. 5.00 mL of 2.08 M NaCl were added to 95.0 mL of serum. The spiked serum gave a signal of 7.98 mV. How much Na + was in th...
【单选题】_____把黑盒子测试和白盒子测试的界限打乱了。